Newbie with runaway fires - Help!

[Sprinter]

Some general thoughts:

1. Normally, by the time the stove top is at even 300, I would think the secondaries and flue should be plenty hot to start the process of turning the air down. The fire should be rolling well by then. If it isn't, it could be the wood. On my stove, I can start turning air down before that even.

2. A full load, even with large splits, on a large hot bed of coals can invite a runaway. Small splits, probably every time. Try not to reload on too hot or large of a bed, at least not too large a load. Usually best to let your coal bed burn down quite a ways.

3. Try using your larger splits along with the smaller hardwood splits, mixed. The dry wood will tend to compensate for the wetter wood. I think Jeff_t is right that the small splits are drying out quickly. I guess that could be a good part of letting the fire get hot before turning down, up to a point.

4. On the chimney length, I meant to ask what is the total flue length, stove to top?

 

[Grisu]

These are on hot coals. I never thought of opening the bypass damper, I suppose I can give that a try. Last night when this problem happened again, I tried reducing air intake around 400F - 450F and it kept choking. So I gave it more air until 500F and that is when the secondaries go crazy and temps begin to spike.

Did you reduce the air slowly in a stepwise fashion or in one fell swoop? Close it by a quarter, wait a bit and watch the fire, close it again a little bit and so on. As long as the secondaries are starting up when you dial down the primary air you are not choking down the fire. For your small splits try to stuff them as close together as possible. I would also think about adding one or two of your oak splits. Your total moisture content will still be around 20% but they may help regulate the fire.

 

[BrotherBart]

how do you make your tin foil stick to the air holes without falling off?

If it in fact is secondary air drawing too hard, the suction will hold a piece of tin foil over the hole all by itself.

 

[lopiliberty]

how do you make your tin foil stick to the air holes without falling off?

I'm assuming you air enters in the front where the air control (secondary air I'm not sure on the endeavor) is as mine does. I get a piece of tin foil large enough to cover the front air intake and bend it around the air control rod. Underneath where the outside air kit is supposed to go was already knocked out at the factory when I purchased the stove so I just lay a piece of foil up against it and it stays there from the suction but the front air control has to be covered first

 

[DianeB]

do you have an ash pan? make sure the door is tightly closed. Some times when I sweep up under the stove, I know I can knock the pan door open a bit by mistake so I now check it after a sweeping. Also, you may want to re-load only when the coals are burnt down well. My husband likes to reload to early (like he did in the Fisher) before bed, but we can get an out of control fire that way too. The newer stoves were designed to burn in cycles. With our old fisher that was airtight, we could choke down and let it smolder (not safe either)

 

[isipwater]

Some general thoughts:

1. Normally, by the time the stove top is at even 300, I would think the secondaries and flue should be plenty hot to start the process of turning the air down. The fire should be rolling well by then. If it isn't, it could be the wood. On my stove, I can start turning air down before that even.

2. A full load, even with large splits, on a large hot bed of coals can invite a runaway. Small splits, probably every time. Try not to reload on too hot or large of a bed, at least not too large a load. Usually best to let your coal bed burn down quite a ways.

3. Try using your larger splits along with the smaller hardwood splits, mixed. The dry wood will tend to compensate for the wetter wood. I think Jeff_t is right that the small splits are drying out quickly. I guess that could be a good part of letting the fire get hot before turning down, up to a point.

4. On the chimney length, I meant to ask what is the total flue length, stove to top?

Yes, I have been reloading on very hot coals, I will try to avoid this.

I will try with mixing the large and mall splits.

The total length of chimney is 12 feet.

 

[isipwater]

Did you reduce the air slowly in a stepwise fashion or in one fell swoop? Close it by a quarter, wait a bit and watch the fire, close it again a little bit and so on. As long as the secondaries are starting up when you dial down the primary air you are not choking down the fire. For your small splits try to stuff them as close together as possible. I would also think about adding one or two of your oak splits. Your total moisture content will still be around 20% but they may help regulate the fire.

I do try to reduce the air slowly in steps as to not choke it.

Yes, will try to mix large and small splits and hope for more controlled results. Thanks.

 

[isipwater]

do you have an ash pan? make sure the door is tightly closed. Some times when I sweep up under the stove, I know I can knock the pan door open a bit by mistake so I now check it after a sweeping. Also, you may want to re-load only when the coals are burnt down well. My husband likes to reload to early (like he did in the Fisher) before bed, but we can get an out of control fire that way too. The newer stoves were designed to burn in cycles. With our old fisher that was airtight, we could choke down and let it smolder (not safe either)

I don't have an ashpan. Yes, I do get impatient so I can get to bed sooner and reload on very hot coals. I will try to avoid this. Thanks.

 

[Sprinter]

The total length of chimney is 12 feet.

That's very short. I wonder if that may contribute to your problem of not being able to turn the air down earlier than you do. Your draft may not be strong enough.

The general rule is 15' minimum, although some including me can get away with 13. Some stove manufactures actually require 15'. Not sure what Lopi recommends.

 

[isipwater]

That's very short. I wonder if that may contribute to your problem of not being able to turn the air down earlier than you do. Your draft may not be strong enough.

The general rule is 15' minimum, although some including me can get away with 13. Some stove manufactures actually require 15'. Not sure what Lopi recommends.

The Lopi Endeavor requires 15' min. However, my Endeavor sits on a pedestal, bringing the total height of the stove to 3 feet. If you add my stove pipe of 12 feet, you get to the 15' min. Plus the pipe is straight, with no bends/elbows. If anything, my draft seems to strong.

 

[rideau]

Measure only from the start of the pipe, where it exits the stove.

 

[mass_burner]

2. A full load, even with large splits, on a large hot bed of coals can invite a runaway. Small splits, probably every time. Try not to reload on too hot or large of a bed, at least not too large a load. Usually best to let your coal bed burn down quite a ways.

You know, I guess this where being greedy helped me. When I get a good strong bed of red hot coals, I figure I ought to milk it, since the heat output at this point is very high. Only when they start to burn down, do I add the larger of my splits. I keep a bin of large and separate bin of smaller splits.

 

[isipwater]

Measure only from the start of the pipe, where it exits the stove.

 

[rideau]

They really do mean the pipe when they refer to system. What difference, for instance, could the stove legs make? Call them and check if you think I am wrong. I think your system is too short.

 

[Sprinter]

You know, I guess this where being greedy helped me. When I get a good strong bed of red hot coals, I figure I ought to milk it, since the heat output at this point is very high. Only when they start to burn down, do I add the larger of my splits. I keep a bin of large and separate bin of smaller splits.

Pretty much what I do too. I do use a lot of small splits, but either for starting or for small hot fires in warmer weather.

 

[Sprinter]

That Lopi manual seems pretty clear about the height. I'm told that some stoves do tolerate shorter flues than others do. Still pretty marginal but it's hard to say if it's causing startup problems. My short flue doesn't cause any problems with starting new fires but I do get a little smoke when I open the door if I'm not careful. Otherwise it seems okay.

Normally, in conversations like this, flue length usually means from the top of the stove to the chimney top. I believe a more formal definition includes the depth of the firebox, though. Kind of confusing sometimes.

 

[isipwater]

They really do mean the pipe when they refer to system. What difference, for instance, could the stove legs make? Call them and check if you think I am wrong. I think your system is too short.

I am not convinced it is too short. The manual is clear that the 15' min includes the legs/pedestal and the stove itself.

What are the symptoms and/or problems of a system that it too short?

As I understand it, a system that is too short will have a sluggish draft and burning. I have the opposite problem.

 

[Sprinter]

As I understand it, a system that is too short will have a sluggish draft and burning. I have the opposite problem.

That's right. I suggested the flue height because I think you said that the fire gets choked off when you try to turn the air down when the stove top is under 450 or something. That could be a symptom of poor draft, but it could be other things as well.

 

[isipwater]

That's right. I suggested the flue height because I think you said that the fire gets choked off when you try to turn the air down when the stove top is under 450 or something. That could be a symptom of poor draft, but it could be other things as well.

Thanks for considering that. What I meant is that under 450F, if I close the air supply all the way or too much is seems to easily choke when burning with oak, not pine. However, when burning with small oak splits, after 500F, temp spikes are hard to control, even when closing the air supply all the way.

 

[Sprinter]

What I meant is that under 450F, if I close the air supply all the way or too much is seems to easily choke when burning with oak, not pine.

Got it. That makes sense then, since the oak is so moist. But then you are getting it hot enough that the water gets evaporated out and goes ballistic because the splits are so small. Sounds like the draft is fine.

When you get the wood situation straightened out, try starting the air turn-down earlier in the process. I think you'll find that the stove actually gets hotter faster and you don't waste so much heat up the flue during that time.

 

[rideau]

If you have sufficient draft, fine. Small splits and an open air supply can cause very hot fires without terrific draft. As Sprinter, I was reacting to your statement about not being able to shut down at low temps. I can start to shut my stove down as soon as the wood is charred and flue temps are over 300. It does not choke. And I don't get runaway fires. Even when I use lots of 1 to 2 inch branches as my fuel in the shoulder season. But lots to me in a shoulder season fire is about 6 or 8 branches...no where near a stove load.

 

[isipwater]

Alright, thanks everyone for your help. My fires are under control. I followed your suggestions, using an IR thermometer and started closing the air intake at 300 - 350F instead of waiting until 500 - 550F, and also paying more attention to how the fire looks. I am also stacking my splits more tightly, north to south, where before I was doing more of a Lincoln log criss-cross. Finally, I am utilizing larger splits with my smaller splits. Problem solved, fires are controlled, back to relaxing by the fire, thanks again

 

[egclassic]

Another thing you can try when you have an overfire is to put a "green" split in there.
I am only on my 3rd season of burning and I have had my fair share of overfires, in fact, it's still a concern for me. I just replaced my door gasket this year and the stove was only put in new three years ago. It seemed to have helped but I think my glass gasket needs replaced as well.
I have had nights where I loaded up the stove before bed (9:00 pm) and have not made it to bed until after 11 or 12 because of an overfire. In fact I remember one night last year where I had to open the front door and some windows in the middle of winter to cool the house down. And by then, most of the load is gone. I am now learning to shut the air down more quickly on reloads, but not allowing it to smolder, and it seems to be working out.

 

[Motor7]

Ohhhh, criss-cross is for start up ONLY. That is how I build my fires, once it's going stack 'em tight.